Triaxial stresses, anisotropic damage, and directional fluid flow across scales

The ability to accurately predict both the magnitude and direction of fluid flow within fractured rocks is paramount for the secure injection of fluids into the subsurfacean essential operation for geothermal energy production and CO2 storage.

Even though the stress conditions at depth control the creation of fractures and the transport of fluids through them, technical difficulties have impeded the replication of crustal conditions in the laboratory, and the knowledge of fracture development comes primarily from experiments conducted under simplified two-dimensional stress conditions.

This limited perspective has restricted the understanding of the interplay between three-dimensional stresses, the geometry of developed fracture networks, and the direction of fluid flow within fractured rocks.

Furthermore, a key challenge for large-scale fluid flow prediction is the extrapolation of results obtained at the laboratory scale (centimetres) to actual reservoir scale (hundreds of meters to kilometres).

This project, TRIFLOW, will use for the first time a novel apparatus to deform samples under representative crustal conditions to establish how 3D stresses influence fracture geometry and directional permeability.

These results will be combined with innovative 3D mapping methods applied to natural examples of fossilised fluid flow in the form of vein networks, and numerical analyses, to study the dynamics of tridimensional fluid flow across scales.

The outcomes of this project are expected to bring substantial advancements to our comprehension of fluid flow dynamics under genuine crustal conditions.

This improved understanding will, in turn, enhance the precision of fluid flow simulations for applications involving the injection of fluids into fractured rocks, thereby contributing to the safety of processes such as geothermal fluid injection for energy generation and CO2 storage, both of which are crucial solutions for reducing greenhouse emissions to the atmosphere.